Detection device and display device

ABSTRACT

According to an aspect, a detection device includes: an insulating substrate; a plurality of photoelectric conversion elements that are arranged in a detection area of the insulating substrate, and each of which is configured to receive light and output a signal corresponding to the received light; a first switching element that is provided for each photoelectric conversion element and includes a first semiconductor, a source electrode, and a drain electrode; and an inorganic insulating layer provided between the photoelectric conversion element and the first switching element in a normal direction of the insulating substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority from Japanese PatentApplication No. 2018-219519 filed on Nov. 22, 2018 and InternationalPatent Application No. PCT/JP2019/043292 filed on Nov. 5, 2019, theentire contents of which are incorporated herein by reference.

BACKGROUND 1. Technical Field

What is disclosed herein relates to a detection device and a displaydevice.

2. Description of the Related Art

In recent years, optical fingerprint sensors (refer, for example, toUnited States Patent Application Publication No. 2018/0012069(US-A-2018/0012069)) are known as fingerprint sensors used, for example,for personal authentication. Such an optical fingerprint sensor includesa photoelectric conversion element that outputs a signal that changeswith an amount of irradiating light. In the fingerprint sensor describedin US-A-2018/0012069, a plurality of such photoelectric conversionelements, such as photodiodes, are arranged on a semiconductorsubstrate.

When thin-film transistors and various types of wiring are formed on aninsulating substrate as a backplane for driving the photoelectricconversion elements, impurities may enter the thin-film transistors whenthe photoelectric conversion elements and electrodes are formed into afilm. This may cause a reduction in reliability of the thin-filmtransistors.

SUMMARY

According to an aspect, a detection device includes: an insulatingsubstrate; a plurality of photoelectric conversion elements that arearranged in a detection area of the insulating substrate, and each ofwhich is configured to receive light and output a signal correspondingto the received light; a first switching element that is provided foreach photoelectric conversion element and includes a firstsemiconductor, a source electrode, and a drain electrode; and aninorganic insulating layer provided between the photoelectric conversionelement and the first switching element in a normal direction of theinsulating substrate.

According to an aspect, a display device includes: the detection devicedescribed above; and a display panel that includes display elements todisplay an image and is disposed so as to face the detection device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating a detection device according to afirst embodiment;

FIG. 2 is a block diagram illustrating a configuration example of thedetection device according to the first embodiment;

FIG. 3 is a circuit diagram illustrating the detection device;

FIG. 4 is a circuit diagram illustrating a partial detection area;

FIG. 5 is a timing waveform diagram illustrating an operation example ofthe detection device;

FIG. 6 is a plan view schematically illustrating the partial detectionarea of the detection device according to the first embodiment;

FIG. 7 is a sectional view taken along line VII-VII′ of FIG. 6;

FIG. 8 is a sectional view illustrating a schematic sectionalconfiguration of a detection device according to a second embodiment;

FIG. 9 is a sectional view illustrating a schematic sectionalconfiguration of a detection device according to a third embodiment;

FIG. 10 is a plan view schematically illustrating the partial detectionarea of a detection device according to a fourth embodiment;

FIG. 11 is a sectional view taken along line XI-XI′ of FIG. 10; and

FIG. 12 is a sectional view illustrating a schematic sectionalconfiguration of a display device according to a fifth embodiment.

DETAILED DESCRIPTION

The following describes embodiments for carrying out the presentinvention in detail with reference to the drawings. The presentinvention is not limited to the description of the embodiments givenbelow. Components described below include those easily conceivable bythose skilled in the art or those substantially identical thereto.Moreover, the components described below can be appropriately combined.What is disclosed herein is merely an example, and the present inventionnaturally encompasses appropriate modifications easily conceivable bythose skilled in the art while maintaining the gist of the invention. Tofurther clarify the description, the drawings schematically illustrate,for example, widths, thicknesses, and shapes of various parts ascompared with actual aspects thereof, in some cases. However, they aremerely examples, and interpretation of the present invention is notlimited thereto. The same element as that illustrated in a drawing thathas already been discussed is denoted by the same reference numeralthrough the description and the drawings, and detailed descriptionthereof will not be repeated in some cases where appropriate.

In this disclosure, when an element is described as being “on” anotherelement, the element can be directly on the other element, or there canbe one or more elements between the element and the other element.

First Embodiment

FIG. 1 is a plan view illustrating a detection device according to afirst embodiment. FIG. 2 is a block diagram illustrating a configurationexample of the detection device according to the first embodiment. Asillustrated in FIG. 1, a detection device 1 includes an insulatingsubstrate 21, a sensor 10, a gate line drive circuit 15, a signal lineselection circuit 16, an analog front-end circuit (hereinafter, called“AFE”) 48, a control circuit 102, and a power supply circuit 103.

As illustrated in FIG. 1, a control board 101 is electrically coupled tothe insulating substrate 21 through a flexible printed circuit board 71.The flexible printed circuit board 71 is provided with the AFE 48. Thecontrol board 101 is provided with the control circuit 102 and the powersupply circuit 103. The control circuit 102 is, for example, a fieldprogrammable gate array (FPGA). The control circuit 102 supplies controlsignals to the sensor 10, the gate line drive circuit 15, and the signalline selection circuit 16 to control a detection operation of the sensor10. The power supply circuit 103 supplies voltage signals including apower supply signal SVS (refer to FIG. 4) to the sensor 10 and the gateline drive circuit 15.

As illustrated in FIG. 1, the insulating substrate 21 has a detectionarea AA and a peripheral area GA. The detection area AA is an areaoverlapping a plurality of photodiodes PD (refer to FIG. 4) included inthe sensor 10. The peripheral area GA is an area outside the detectionarea AA, and is an area not overlapping the photodiodes PD. That is, theperipheral area GA is an area between the outer circumference of thedetection area AA and the edges of the insulating substrate 21. The gateline drive circuit 15 and the signal line selection circuit 16 areprovided in the peripheral area GA.

As illustrated in FIG. 2, the detection device 1 further includes adetection controller 11 and a detector 40. The control circuit 102includes some or all functions of the detection controller 11. Thecontrol circuit 102 also includes some or all functions of the detector40 except those of the AFE 48.

The sensor 10 is an optical sensor including the photodiodes PD servingas photoelectric conversion elements. Each of the photodiodes PDincluded in the sensor 10 outputs an electrical signal corresponding tolight emitted thereto as a detection signal Vdet to the signal lineselection circuit 16. The sensor 10 performs the detection in responseto a gate drive signal VGCL supplied from the gate line drive circuit15.

The detection controller 11 is a circuit that supplies respectivecontrol signals to the gate line drive circuit 15, the signal lineselection circuit 16, and the detector 40 to control operations thereof.The detection controller 11 supplies various control signals including astart signal STV, a clock signal CK, and a reset signal RST1 to the gateline drive circuit 15. The detection controller 11 also supplies variouscontrol signals including a selection signal SEL to the signal lineselection circuit 16.

The gate line drive circuit 15 drives a plurality of gate lines GCL(refer to FIG. 3) based on the various control signals. The gate linedrive circuit 15 sequentially or simultaneously selects the gate linesGCL and supplies the gate drive signals VGCL to the selected gate linesGCL. Through this operation, the gate line drive circuit 15 selects thephotodiodes PD coupled to the gate lines GCL.

The signal line selection circuit 16 is a switch circuit thatsequentially or simultaneously selects a plurality of signal lines SGL(refer to FIG. 3). The signal line selection circuit 16 couples theselected signal lines SGL to the AFE 48 based on the selection signalSEL supplied from the detection controller 11. Through this operation,the signal line selection circuit 16 outputs the detection signal Vdetof each of the photodiodes PD to the detector 40. The signal lineselection circuit 16 is, for example, a multiplexer.

The detector 40 includes the AFE 48, a signal processor 44, a coordinateextractor 45, a storage 46, and a detection timing controller 47. Thedetection timing controller 47 controls, based on a control signalsupplied from the detection controller 11, the AFE 48, the signalprocessor 44, and the coordinate extractor 45 such that they operate insynchronization with one another.

The AFE 48 is a signal processing circuit having functions of at least adetection signal amplifier 42 and an analog-to-digital (A/D) converter43. The detection signal amplifier 42 amplifies the detection signalVdet. The A/D converter 43 converts an analog signal output from thedetection signal amplifier 42 into a digital signal.

The signal processor 44 is a logic circuit that detects, based on anoutput signal of the AFE 48, a predetermined physical quantity receivedby the sensor 10. When a finger is in contact with or in proximity to adetection surface, the signal processor 44 can detect asperities of asurface of the finger or a palm based on the signal from the AFE 48.

The storage 46 temporarily stores a signal calculated by the signalprocessor 44. The storage 46 may be, for example, a random-access memory(RAM) or a register circuit.

The coordinate extractor 45 is a logic circuit that obtains detectedcoordinates of the asperities of the surface of, for example, the fingerwhen the contact or the proximity of the finger is detected by thesignal processor 44. The coordinate extractor 45 combines the detectionsignals Vdet output from the respective photodiodes PD of the sensor 10to generate two-dimensional information representing a shape of theasperities of the surface of, for example, the finger. The coordinateextractor 45 may output the detection signals Vdet as sensor outputs Vo,without calculating the detected coordinates.

The following describes a circuit configuration example and an operationexample of the detection device 1. FIG. 3 is a circuit diagramillustrating the detection device. FIG. 4 is a circuit diagramillustrating a partial detection area. FIG. 5 is a timing waveformdiagram illustrating the operation example of the detection device.

As illustrated in FIG. 3, the sensor 10 has a plurality of partialdetection areas PAA arranged in a matrix having a row-columnconfiguration. As illustrated in FIG. 4, each of the partial detectionareas PAA includes the photodiode PD, a capacitive element Ca, and afirst switching element Tr. The first switching element Tr is providedcorresponding to the photodiode PD. The first switching element Trincludes a thin-film transistor, and in this example, includes ann-channel metal oxide semiconductor (MOS) thin-film transistor (TFT).The gate of the first switching element Tr is coupled to each of thegate lines GCL. The source of the first switching element Tr is coupledto each of the signal lines SGL. The drain of the first switchingelement Tr is coupled to the anode of the photodiode PD and thecapacitive element Ca.

The cathode of the photodiode PD is supplied with the power supplysignal SVS from the power supply circuit 103. The capacitive element Cais supplied with a reference signal VR1 serving as an initial potentialof the capacitive element Ca from the power supply circuit 103.

When the partial detection area PAA is irradiated with light, a currentcorresponding to an amount of the light flows through the photodiode PD.As a result, an electrical charge is stored in the capacitive elementCa. After the first switching element Tr is turned on, a currentcorresponding to the electrical charge stored in the capacitive elementCa flows through the signal line SGL. The signal line SGL is coupled tothe AFE 48 through the signal line selection circuit 16. Thus, thedetection device 1 can detect a signal corresponding to the amount ofthe light emitted to the photodiode PD for each of the partial detectionareas PAA.

As illustrated in FIG. 3, the gate lines GCL extend in a first directionDx and are coupled to the partial detection areas PAA arranged in thefirst direction Dx. A plurality of gate lines GCL1, GCL2, GCL8 arearranged in a second direction Dy and are each coupled to the gate linedrive circuit 15. In the following description, the gate lines GCL1,GCL2, GCL8 will each be simply referred to as the gate line GCL whenneed not be distinguished from one another. Although the number of thegate lines GCL is eight, this is merely an example. Eight or more, suchas 256, of the gate lines GCL may be arranged.

The first direction Dx is a direction in a plane parallel to theinsulating substrate 21 and is, for example, a direction parallel to thegate lines GCL. The second direction Dy is a direction in a planeparallel to the insulating substrate 21 and is, for example, a directionorthogonal to the first direction Dx. The second direction Dy mayintersect the first direction Dx without being orthogonal thereto. Thenormal direction of the insulating substrate 21 is a directionorthogonal to the first direction Dx and the second direction Dy.

The signal lines SGL extend in the second direction Dy and are coupledto the partial detection areas PAA arranged in the second direction Dy.A plurality of signal lines SGL1, SGL2, SGL12 are arranged in the firstdirection Dx and are each coupled to the signal line selection circuit16 and a reset circuit 17. Although the number of the signal lines SGLis 12, this is merely an example. Twelve or more, such as 252, of thesignal lines SGL may be arranged. In FIG. 3, the sensor 10 is providedbetween the signal line selection circuit 16 and the reset circuit 17.The present disclosure is not limited thereto. The signal line selectioncircuit 16 and the reset circuit 17 may be coupled to the same ends ofthe signal lines SGL.

The gate line drive circuit 15 receives the various control signals suchas the start signal STV, the clock signal CK, and the reset signal RST1through a level shifter 151. The gate line drive circuit 15 includes aplurality of second switching elements TrG (refer to FIG. 7). The gateline drive circuit 15 sequentially selects the gate lines GCL1, GCL2,GCL8 in a time-division manner by operations of the second switchingelements TrG. The gate line drive circuit 15 supplies the gate drivesignals VGCL to the first switching elements Tr through the selectedgate lines GCL. This operation selects the partial detection areas PAAarranged in the first direction Dx as detection targets.

The signal line selection circuit 16 includes a plurality of selectionsignal lines Lsel, a plurality of output signal lines Lout, and thirdswitching elements TrS. The third switching elements TrS are providedcorresponding to the signal lines SGL. Six of the signal lines SGL1,SGL2, SGL6 are coupled to a common output signal line Lout1. Six of thesignal lines SGL7, SGL8, SGL12 are coupled to a common output signalline Lout2. The output signal lines Lout1 and Lout2 are each coupled tothe AFE 48.

The signal lines SGL1, SGL2, SGL6 are grouped into a first signal lineblock, and the signal lines SGL7, SGL8, SGL12 are grouped into a secondsignal line block. The selection signal lines Lsel are coupled to thegates of the respective third switching elements TrS included in one ofthe signal line blocks. One of the selection signal lines Lsel iscoupled to the gates of the third switching elements TrS in the signalline blocks. Specifically, selection signal lines Lsel1, Lse12, Lsel6are respectively coupled to the third switching elements TrScorresponding to the signal lines SGL1, SGL2, SGL6. The selection signalline Lsel1 is coupled to the third switching element TrS correspondingto the signal line SGL1 and the third switching element TrScorresponding to the signal line SGL7. The selection signal line Lsel2is coupled to the third switching element TrS corresponding to thesignal line SGL2 and the third switching element TrS corresponding tothe signal line SGL8.

The control circuit 102 (refer to FIG. 1) sequentially supplies theselection signals SEL to the selection signal lines Lsel through levelshifters 161. This operation causes the signal line selection circuit 16to operate the third switching elements TrS to sequentially select thesignal lines SGL in each of the signal line blocks in a time-divisionmanner. The signal line selection circuit 16 simultaneously selects onesignal line SGL in each of the signal line blocks. With theabove-described configuration, the detection device 1 can reduce thenumber of integrated circuits (ICs) including the AFE 48 or the numberof terminals of the ICs.

As illustrated in FIG. 3, the reset circuit 17 includes a referencesignal line Lvr, a reset signal line Lrst, and fourth switching elementsTrR. The fourth switching elements TrR are provided corresponding to thesignal lines SGL. The reference signal line Lvr is coupled to either thesources or the drains of the fourth switching elements TrR. The resetsignal line Lrst is coupled to the gates of the fourth switchingelements TrR.

The control circuit 102 supplies a reset signal RST2 to the reset signalline Lrst through a level shifter 171. This operation turns on thefourth switching elements TrR to electrically couple the signal linesSGL to the reference signal line Lvr. The power supply circuit 103supplies the reference signal VR1 to the reference signal line Lvr. Thisoperation supplies the reference signal VR1 to the capacitive elementsCa included in the partial detection areas PAA.

As illustrated in FIG. 5, the detection device 1 includes a reset periodPrst, an exposure period Pex, and a reading period Pdet. The powersupply circuit 103 supplies the power supply signal SVS to the cathodeof the photodiode PD through the reset period Prst, the exposure periodPex, and the reading period Pdet. The control circuit 102 supplies thereference signal VR1 and the reset signal RST2 serving as high-levelvoltage signals to the reset circuit 17 from a time before the resetperiod Prst starts. The control circuit 102 supplies the start signalSTV to the gate line drive circuit 15, and the reset period Prst starts.

During the reset period Prst, a shift register included in the gate linedrive circuit 15 sequentially selects each of the gate lines GCL basedon the start signal STV, the clock signal CK, and the reset signal RST1.The gate line drive circuit 15 sequentially supplies the gate drivesignals VGCL to the gate lines GCL. The gate drive signal VGCL has apulsed waveform having a high-level voltage VGH and a low-level voltageVGL. In FIG. 5, 256 gate lines GCL are provided, and gate drive signalsVGCL1, . . . , VGCL256 are sequentially supplied to the gate lines GCL.

Thus, during the reset period Prst, the capacitive elements Ca of allthe partial detection areas PAA are sequentially electrically coupled tothe signal lines SGL and are supplied with the reference signal VR1. Asa result, capacitances of the capacitive elements Ca are reset.

After the gate drive signal VGCL256 is supplied to the gate line GCL,the exposure period Pex starts. The start timing and end timing ofactual exposure periods Pex1, . . . , Pex256 in the partial detectionareas PAA corresponding to the gate lines GCL differ from one another.Each of the exposure periods Pex1, . . . , Pex256 starts at a time whenthe gate drive signal VGCL changes from the high-level voltage VGH tothe low-level voltage VGL during the reset period Prst. Each of theexposure periods Pex1, . . . , Pex256 ends at a time when the gate drivesignal VGCL changes from the low-level voltage VGL to the high-levelvoltage VGH during the reading period Pdet. The lengths of exposure timeof the exposure periods Pex1, . . . , Pex256 are equal.

During the exposure period Pex, the current corresponding to the lightemitted to the photodiode PD flows in each of the partial detectionareas PAA. As a result, the electrical charge is stored in each of thecapacitive elements Ca.

At a time before the reading period Pdet starts, the control circuit 102sets the reset signal RST2 to a low-level voltage. This operation stopsthe operation of the reset circuit 17. During the reading period Pdet,the gate line drive circuit 15 sequentially supplies the gate drivesignals VGCL1, . . . , VGCL256 to the gate lines GCL in the same manneras during the reset period Prst.

For example, during a period in which the gate drive signal VGCL1 is atthe high-level voltage VGH, the control circuit 102 sequentiallysupplies selection signals SEL1, SEL6 to the signal line selectioncircuit 16. With this operation, the signal lines SGL for the partialdetection areas PAA selected by the gate drive signal VGCL1 aresequentially or simultaneously coupled to the AFE 48. As a result, thedetection signal Vdet is supplied to the AFE 48. In the same manner, thesignal line selection circuit 16 sequentially selects the signal lineSGL in each period in which a corresponding one of the gate drivesignals VGCL is set to the high-level voltage VGH. Thus, the detectiondevice 1 can output the detection signals Vdet of all the partialdetection areas PAA to the AFE 48 during the reading period Pdet.

The detection device 1 may perform the fingerprint detection byrepeatedly performing the processing during the reset period Prst, theexposure period Pex, and the reading period Pdet. Alternatively, thedetection device 1 may start the detection operation when havingdetected that a finger, for example, is in contact with or in proximityto the detection surface.

The following describes a detailed configuration of the detection device1. FIG. 6 is a plan view schematically illustrating the partialdetection area of the detection device according to the firstembodiment. FIG. 7 is a sectional view taken along line VII-VII′ of FIG.6. To illustrate a relation between a layered structure of the detectionarea AA and a layered structure of the peripheral area GA, FIG. 7illustrates the section taken along line VII-VII′ and a section of aportion of the peripheral area GA including one of the second switchingelements TrG in a schematically connected manner. FIG. 7 alsoillustrates a section of a portion of the peripheral area GA including aterminal portion 72 in a schematically connected manner.

In the description of the detection device 1, in a direction orthogonalto a surface of the insulating substrate 21, the term “above (upperside)” refers to a direction from the insulating substrate 21 toward thephotodiode PD, and the term “below (lower side)” refers to a directionfrom the photodiode PD toward the insulating substrate 21. The term“plan view” refers to a case of viewing from the direction orthogonal tothe surface of the insulating substrate 21.

As illustrated in FIG. 6, the partial detection area PAA is an areasurrounded by the gate lines GCL and the signal lines SGL. In thepresent embodiment, the gate line GCL includes a first gate line GCLAand a second gate line GCLB. The first gate line GCLA is provided so asto overlap the second gate line GCLB. The first gate line GCLA and thesecond gate line GCLB are provided in different layers with insulatinglayers (a fifth inorganic insulating layer 22 c and a sixth inorganicinsulating layer 22 d (refer to FIG. 7)) interposed therebetween. Thefirst gate line GCLA and the second gate line GCLB are electricallycoupled to each other at any place and are supplied with the gate drivesignals VGCL having the same potential. At least one of the first gateline GCLA and the second gate line GCLB is coupled to the gate linedrive circuit 15. In FIG. 6, the first gate line GCLA has a differentwidth from that of the second gate line GCLB. However, the first gateline GCLA may have the same width as that of the second gate line GCLB.

The photodiode PD is provided in the area surrounded by the gate linesGCL and the signal lines SGL. The photodiode PD includes a thirdsemiconductor 31, an upper electrode 34, and a lower electrode 35. Thephotodiode PD is, for example, a positive-intrinsic-negative (PIN)photodiode.

As illustrated in FIG. 6, the upper electrode 34 is coupled to a powersupply signal line Lvs through coupling wiring 36. The power supplysignal line Lvs is wiring that supplies the power supply signal SVS tothe photodiode PD. In the present embodiment, the power supply signalline Lvs extends in the second direction Dy so as to overlap the signalline SGL. The partial detection areas PAA arranged in the seconddirection Dy are coupled to the common power supply signal line Lvs.Such a configuration allows the partial detection area PAA to have alarger opening. The lower electrode 35, the third semiconductor 31, andthe upper electrode 34 have a quadrilateral shape in the plan view.However, the shape of the lower electrode 35, the third semiconductor31, and the upper electrode 34 is not limited thereto, and can bechanged as appropriate.

The first switching element Tr is provided near an intersecting portionbetween the gate line GCL and the signal line SGL. The first switchingelement Tr includes a first semiconductor 61, a source electrode 62, adrain electrode 63, a first gate electrode 64A, and a second gateelectrode 64B.

The first semiconductor 61 is an oxide semiconductor. The firstsemiconductor 61 is more preferably a transparent amorphous oxidesemiconductor (TAOS) among types of the oxide semiconductor. Using theoxide semiconductor as the first switching element Tr can reduce aleakage current of the first switching element Tr. That is, the firstswitching element Tr can reduce the leakage current from the partialdetection area PAA that is not selected during the reading period Pdetillustrated in FIG. 5. As a result, the detection device 1 can increasea signal-to-noise (S/N) ratio.

The first semiconductor 61 is provided along the first direction Dx andintersects the first gate electrode 64A and the second gate electrode64B in a plan view. The first gate electrode 64A and the second gateelectrode 64B are provided so as to branch from the first gate line GCLAand the second gate line GCLB, respectively. In other words, portions ofthe first gate line GCLA and the second gate line GCLB overlapping thefirst semiconductor 61 serve as the first gate electrode 64A and thesecond gate electrode 64B. Aluminum (Al), copper (Cu), silver (Ag),molybdenum (Mo), or an alloy of these materials is used as the firstgate electrode 64A and the second gate electrode 64B. A channel area isformed at a portion of the first semiconductor 61 overlapping the firstgate electrode 64A and the second gate electrode 64B.

One end of the first semiconductor 61 is coupled to the source electrode62 through a contact hole H1. The other end of the first semiconductor61 is coupled to the drain electrode 63 through a contact hole H2. Aportion of the signal line SGL overlapping the first semiconductor 61serves as the source electrode 62. A portion of a third conductive layer67 overlapping the first semiconductor 61 serves as the drain electrode63. The third conductive layer 67 is coupled to the lower electrode 35through a contact hole H3. The above-described configuration allows thefirst switching element Tr to switch between coupling and decoupling ofthe photodiode PD to and from the signal line SGL.

The following describes a layer configuration of the first switchingelement Tr and the photodiode PD. As illustrated in FIG. 7, thephotodiode PD is provided on the upper side of a backplane 2. Thebackplane 2 is a drive circuit board that drives the sensor on a perpredetermined partial detection area PAA basis. The backplane 2 includesthe insulating substrate 21, and the first switching element Tr, thesecond switching element TrG, and various types of wiring provided onthe insulating substrate 21.

The first switching element Tr is provided on the insulating substrate21. The insulating substrate 21 is, for example, a glass substrate.Alternatively, the insulating substrate 21 may be a resin substrate or aresin film formed of a resin such as polyimide. In the detection device1, the first switching element Tr including the oxide semiconductor isformed above the insulating substrate 21. This configuration allows thedetection device 1 to have an area of the detection area AA larger thanthat in a case of using a semiconductor substrate such as a siliconsubstrate.

The second gate electrode 64B is provided above the insulating substrate21 with a third inorganic insulating layer 22 a and a fourth inorganicinsulating layer 22 b interposed therebetween. For example, a siliconoxide (SiO) film, a silicon nitride (SiN) film, or a silicon oxynitride(SiON) film is used as each of the third to a ninth inorganic insulatinglayers 22 a to 22 g. Each of the inorganic insulating layers is notlimited to a single layer, but may be a multi-layered film.

The fifth inorganic insulating layer 22 c is provided on the upper sideof the fourth inorganic insulating layer 22 b so as to cover the secondgate electrode 64B. The first semiconductor 61, a first conductive layer65, and a second conductive layer 66 are provided on the upper side ofthe fifth inorganic insulating layer 22 c. The first conductive layer 65is provided so as to cover an end of the first semiconductor 61 coupledto the source electrode 62. The second conductive layer 66 is providedso as to cover an end of the first semiconductor 61 coupled to the drainelectrode 63.

The sixth inorganic insulating layer 22 d is provided above the fifthinorganic insulating layer 22 c so as to cover the first semiconductor61, the first conductive layer 65, and the second conductive layer 66.The first gate electrode 64A is provided above the sixth inorganicinsulating layer 22 d. The first semiconductor 61 is provided betweenthe first gate electrode 64A and the second gate electrode 64B in adirection orthogonal to the insulating substrate 21. That is, the firstswitching element Tr has what is called a dual-gate structure. However,the first switching element Tr may have a top-gate structure in whichthe first gate electrode 64A is provided while the second gate electrode64B is not provided, or a bottom-gate structure in which only the secondgate electrode 64B is provided without the first gate electrode 64Abeing provided.

The seventh inorganic insulating layer 22 e is provided on the upperside of the sixth inorganic insulating layer 22 d so as to cover thefirst gate electrode 64A. The source electrode 62 (signal line SGL) andthe drain electrode 63 (third conductive layer 67) are provided on theupper side of the seventh inorganic insulating layer 22 e. In thepresent embodiment, the drain electrode 63 is the third conductive layer67 provided above the first semiconductor 61 with the sixth inorganicinsulating layer 22 d and the seventh inorganic insulating layer 22 einterposed therebetween. The fifth to the seventh inorganic insulatinglayers 22 c to 22 e are interlayer insulating layers for insulationbetween layers of the first switching element Tr, and the sourceelectrode 62 and the drain electrode 63 are provided above the firstsemiconductor 61 with the interlayer insulating layers interposedtherebetween. The sixth and the seventh inorganic insulating layers 22 dand 22 e are provided with the contact holes H1 and H2. The firstconductive layer 65 is exposed at the bottom of the contact hole H1. Thesource electrode 62 is electrically coupled to the first semiconductor61 through the contact hole H1 and the first conductive layer 65. In thesame manner, the second conductive layer 66 is exposed at the bottom ofthe contact hole H2. The drain electrode 63 is electrically coupled tothe first semiconductor 61 through the contact hole H2 and the secondconductive layer 66.

The first conductive layer 65 is provided at a portion overlapping atleast the bottom of the contact hole H1 between the source electrode 62and the first semiconductor 61, and contacts the first semiconductor 61.The second conductive layer 66 is provided at a portion overlapping atleast the bottom of the contact hole H2 between the drain electrode 63and the first semiconductor 61, and contacts the first semiconductor 61.Since the detection device 1 is provided with the first conductive layer65 and the second conductive layer 66, the first semiconductor 61 can berestrained from being removed by an etching solution when the contactholes H1 and H2 are formed by etching. That is, in the detection device1, the first switching elements Tr in the detection area AA and thesecond switching elements TrG in the peripheral area GA can be formed inthe same process, so that the manufacturing cost can be reduced.

A metal material such as aluminum (Al), copper (Cu), silver (Ag), ormolybdenum (Mo), or an alloy of these materials is used as the firstconductive layer 65, the second conductive layer 66, and the thirdconductive layer 67. The first conductive layer 65 and the secondconductive layer 66 only need to be made of a conductive material thatrestrains the etching from progressing when the contact holes H1 and H2are formed.

The third conductive layer 67 is provided in an area overlapping thephotodiode PD in the plan view. The third conductive layer 67 is alsoprovided on the upper side of the first semiconductor 61, the first gateelectrode 64A, and the second gate electrode 64B. That is, the thirdconductive layer 67 is provided between the first gate electrode 64A andthe lower electrode 35 in the direction orthogonal to the insulatingsubstrate 21. This configuration causes the third conductive layer 67 tohave a function as a protection layer for protecting the first switchingelement Tr.

The second conductive layer 66 extends so as to face the thirdconductive layer 67 in an area not overlapping the first semiconductor61. A fourth conductive layer 68 is provided on the upper side of thesixth inorganic insulating layer 22 d in an area not overlapping thefirst semiconductor 61. The fourth conductive layer 68 is providedbetween the second conductive layer 66 and the third conductive layer67. This configuration forms a capacitance between the second conductivelayer 66 and the fourth conductive layer 68, and a capacitance betweenthe third conductive layer 67 and the fourth conductive layer 68. Thecapacitances formed by the second conductive layer 66, the thirdconductive layer 67, and the fourth conductive layer 68 serve as acapacitance of the capacitive element Ca illustrated in FIG. 4.

A first organic insulating layer 23 a is provided on the upper side ofthe seventh inorganic insulating layer 22 e so as to cover the sourceelectrode 62 (signal line SGL) and the drain electrode 63 (thirdconductive layer 67). The first organic insulating layer 23 a is aplanarizing layer that planarizes asperities formed by the firstswitching elements Tr and various types of conductive layers.

A first inorganic insulating layer 25 is provided between the firstorganic insulating layer 23 a and the photodiode PD in the normaldirection of the insulating substrate 21. The first inorganic insulatinglayer 25 covers an upper surface of the first organic insulating layer23 a. The lower electrode 35 of the photodiode PD is provided on theupper side of the first inorganic insulating layer 25. In other words,the first inorganic insulating layer 25 is provided between thephotodiode PD and the first switching element Tr in the normal directionof the insulating substrate 21. The first inorganic insulating layer 25is continuously provided over the partial detection areas PAA in theplan view. The first inorganic insulating layer 25 may be provided foreach of the partial detection areas PAA, or may be provided over areasoverlapping the photodiodes PD and areas overlapping the first switchingelements Tr.

For example, an aluminum oxide (Al₂O₃) film, a silicon oxide (SiO) film,a silicon nitride (SiN) film, or a silicon oxynitride (SiON) film isused as the first inorganic insulating layer 25. The first inorganicinsulating layer 25 is not limited to a single layer, but may be amultilayered film.

As illustrated in FIG. 7, the photodiode PD is stacked in the order ofthe lower electrode 35, the third semiconductor 31, and the upperelectrode 34 on the first inorganic insulating layer 25 of the backplane2.

The third semiconductor 31 is of amorphous silicon (a-Si). The thirdsemiconductor 31 includes an i-type semiconductor 32 a, a p-typesemiconductor 32 b, and an n-type semiconductor 32 c. The i-typesemiconductor 32 a, the p-type semiconductor 32 b, and the n-typesemiconductor 32 c are specific examples of the photoelectric conversionelements. In FIG. 7, the n-type semiconductor 32 c, the i-typesemiconductor 32 a, and the p-type semiconductor 32 b are stacked in theorder as listed in the direction orthogonal to the surface of theinsulating substrate 21. However, a reversed configuration may beemployed. That is, the p-type semiconductor 32 b, the i-typesemiconductor 32 a, and the n-type semiconductor 32 c may be stacked inthe order as listed.

The lower electrode 35 is the anode of the photodiode PD and is anelectrode for reading the detection signal Vdet. For example, a metalmaterial such as molybdenum (Mo) or aluminum (Al) is used as the lowerelectrode 35. Alternatively, the lower electrode 35 may be amultilayered film having a plurality of stacked layers of these metalmaterials. The lower electrode 35 may be of a light-transmittingconductive material such as indium tin oxide (ITO).

The lower electrode 35 is electrically coupled to the third conductivelayer 67 through the contact hole H3 provided in the first organicinsulating layer 23 a and an opening 25 a provided in the firstinorganic insulating layer 25. The opening 25 a is provided so as tocommunicate with the contact hole H3. The third conductive layer 67 iselectrically coupled to the lower electrode 35 serving as the anode ofthe photodiode PD, and is provided between the photodiode PD and thefirst gate electrode 64A of the first switching element Tr.

The a-Si of the n-type semiconductor 32 c is doped with impurities toform an n+ region. The a-Si of the p-type semiconductor 32 b is dopedwith impurities to form a p+ region. The i-type semiconductor 32 a is,for example, a non-doped intrinsic semiconductor and has lowerconductivity than those of the n-type semiconductor 32 c and the p-typesemiconductor 32 b.

The upper electrode 34 is the cathode of the photodiode PD and is anelectrode for supplying the power supply signal SVS to the photoelectricconversion layer. The upper electrode 34 is a light-transmittingconductive layer of, for example, ITO. The upper electrode 34 isprovided for each of the photodiodes PD on a one-by-one basis.

The eighth inorganic insulating layer 22 f and the ninth inorganicinsulating layer 22 g are provided on the upper side of the firstinorganic insulating layer 25. The eighth inorganic insulating layer 22f covers a peripheral portion of the upper electrode 34 and is providedwith an opening in a position overlapping the upper electrode 34. Thecoupling wiring 36 is coupled to the upper electrode 34 at a portion ofthe upper electrode 34 not provided with the eighth inorganic insulatinglayer 22 f The ninth inorganic insulating layer 22 g is provided on theupper side of the eighth inorganic insulating layer 22 f so as to coverthe upper electrode 34 and the coupling wiring 36. A second organicinsulating layer 23 b serving as a planarizing layer is provided on theupper side of the ninth inorganic insulating layer 22 g.

The second switching elements TrG of the gate line drive circuit 15 isprovided in the peripheral area GA. The second switching elements TrGand the first switching elements Tr are provided on the same insulatingsubstrate 21. The second switching element TrG includes a secondsemiconductor 81, a source electrode 82, a drain electrode 83, and agate electrode 84.

The second semiconductor 81 is of polysilicon. The second semiconductor81 is more preferably of low-temperature polysilicon (hereinafter,referred to as low-temperature polycrystalline silicon (LTPS)). Thesecond switching element TrG using LTPS can be produced at a processtemperature of 600 degrees Celsius or lower. Therefore, circuits such asthe gate line drive circuit 15 and the signal line selection circuit 16as well as the first switching elements Tr can be formed on the samesubstrate. Polysilicon has higher carrier mobility than that of a-Si.Therefore, the size of the gate line drive circuit 15 in the detectiondevice 1 can be reduced by using polysilicon as the second switchingelements TrG. As a result, the area of the peripheral area GA in thedetection device 1 can be reduced. The second switching element TrGusing polysilicon has higher reliability than that obtained using a-Si.

The second semiconductor 81 is provided on the upper side of the thirdinorganic insulating layer 22 a. That is, the first semiconductor 61 ofthe first switching element Tr is provided in a position farther awayfrom the insulating substrate 21 than the second semiconductor 81 of thesecond switching element TrG in the direction orthogonal to theinsulating substrate 21. This configuration allows the secondsemiconductor 81 formed of polysilicon and the first semiconductor 61formed of the oxide semiconductor to be formed on the same insulatingsubstrate 21.

The gate electrode 84 is provided above the second semiconductor 81 withthe fourth inorganic insulating layer 22 b interposed therebetween. Thegate electrode 84 is provided in the same layer as that of the secondgate electrode 64B. The second switching element TrG has what is calledthe top-gate structure. However, the second switching element TrG mayhave the dual-gate structure or the bottom-gate structure.

The source electrode 82 and the drain electrode 83 are provided on theupper side of the seventh inorganic insulating layer 22 e. The sourceelectrode 82 and the drain electrode 83 are provided in the same layeras that of the source electrode 62 and the drain electrode 63 of thefirst switching element Tr. Contact holes H4 and H5 are provided throughfrom the fourth inorganic insulating layer 22 b to the seventh inorganicinsulating layer 22 e. The source electrode 82 is electrically coupledto the second semiconductor 81 through the contact hole H4. The drainelectrode 83 is electrically coupled to the second semiconductor 81through the contact hole H5.

The contact holes H4 and H5 are formed in four of the inorganicinsulating layers (fourth to seventh inorganic insulating layers 22 b to22 e), and the contact holes H1 and H2 are formed in two of theinorganic insulating layers (sixth and seventh inorganic insulatinglayers 22 d and 22 e). That is, the length of the contact holes H4 andH5 in the direction orthogonal to the insulating substrate 21 is greaterthan that of the contact holes H1 and H2. Even in this case, the contactholes H1 and H2 and the contact holes H4 and H5 of the detection device1 can be formed in the same process because the first switching elementTr is provided with the first conductive layer 65 and the secondconductive layer 66.

The first inorganic insulating layer 25 is provided across the detectionarea AA and the peripheral area GA. That is, the first inorganicinsulating layer 25 is provided over an area overlapping the secondswitching element TrG.

Each of the third switching elements TrS included in the signal lineselection circuit 16 illustrated in FIG. 3 may have the sameconfiguration as that of the second switching element TrG. That is, thesemiconductor of the third switching element TrS is of polysilicon, andis more preferably of LTPS. In this case, the circuit scale of thesignal line selection circuit 16 of the detection device 1 can bereduced. The semiconductor of the third switching element TrS is notlimited to such materials, but may be an oxide semiconductor including aTAOS. In the same manner, each of the fourth switching elements TrRincluded in the reset circuit 17 illustrated in FIG. 3 may also have thesame configuration as that of the second switching element TrG. That is,the semiconductor of the fourth switching elements TrR is ofpolysilicon, and is more preferably of LTPS. In this case, the circuitscale of the reset circuit 17 of the detection device 1 can be reduced.The semiconductor of the fourth switching elements TrR is not limited tosuch materials but may be an oxide semiconductor including a TAOS.

The terminal portion 72 is provided in a position of the peripheral areaGA different from the area provided with the gate line drive circuit 15.The terminal portion 72 includes a first terminal conductive layer 73, asecond terminal conductive layer 74, a third terminal conductive layer75, and a fourth terminal conductive layer 76. The first terminalconductive layer 73 is provided in the same layer as that of the secondgate electrode 64B and on the fourth inorganic insulating layer 22 b. Acontact hole H6 is provided so as to extend through the fifth inorganicinsulating layer 22 c, the sixth inorganic insulating layer 22 d, theseventh inorganic insulating layer 22 e, and the first organicinsulating layer 23 a.

The second terminal conductive layer 74, the third terminal conductivelayer 75, and the fourth terminal conductive layer 76 are stacked in thecontact hole H6 in the order as listed and are electrically coupled tothe first terminal conductive layer 73. The second terminal conductivelayer 74 can be formed using the same material as and in the sameprocess as those of the third conductive layer 67 and the like. Thethird terminal conductive layer 75 can be formed using the same materialas and in the same process as those of the lower electrode 35. Thefourth terminal conductive layer 76 can be formed using the samematerial as and in the same process as those of the coupling wiring 36and the power supply signal line Lvs (refer to FIG. 6).

Although FIG. 7 illustrates one terminal portion 72, a plurality of suchterminal portions 72 are arranged with gaps interposed therebetween. Theterminal portions 72 are electrically coupled to the flexible printedcircuit board 71 (refer to FIG. 1) through, for example, an anisotropicconductive film (ACF).

As described above, the detection device 1 of the present embodimentincludes the insulating substrate 21, the photoelectric conversionelements (photodiodes PD) that are arranged in the detection area AA ofthe insulating substrate 21 and each output the signal corresponding tothe light emitted thereto, the first switching elements Tr that areprovided corresponding to the photoelectric conversion elements and eachinclude the first semiconductor 61, the source electrode 62, and thedrain electrode 63, and the first inorganic insulating layer 25 providedbetween the photoelectric conversion elements and the first switchingelements Tr in the normal direction of the insulating substrate 21.

This configuration allows the first inorganic insulating layer 25 torestrain hydrogen (H) generated from the photodiode PD from beingdiffused to the first switching element Tr. That is, the first inorganicinsulating layer 25 serves as a barrier layer that reduces permeation ofhydrogen (H). Hydrogen (H) is generated from the photodiode PD, forexample, when the third semiconductor 31 of amorphous silicon (a-Si) isformed into a film, and when the lower electrode 35 formed of ITO istreated with heat. Thus, in the detection device 1, it is possible toreduce changes in characteristics of, for example, the firstsemiconductor 61 of the first switching element Tr that would be causedby the diffusion of hydrogen (H) so as to ensure reliability.

The detection device 1 of the present embodiment also includes theplanarizing film (first organic insulating layer 23 a) covering thefirst switching element Tr, and the first inorganic insulating layer 25is provided between the planarizing film and the photoelectricconversion element in the normal direction of the insulating substrate21.

This configuration allows the first inorganic insulating layer 25 toreduce an influence on the planarizing film in the manufacturing processof the photodiode PD. Although the configuration has been described inwhich amorphous silicon (a-Si) is used as the photodiode PD, theconfiguration is not limited thereto. An organic material may be usedfor the photodiode PD. Even in this case, the first inorganic insulatinglayer 25 prevents the organic material of the photodiode PD fromcontacting the first organic insulating layer 23 a, so that theinfluence on the planarizing film can be reduced in the manufacturingprocess of the photodiode PD.

In the detection device 1 of the present embodiment, the sourceelectrode 62 and the drain electrode 63 are provided above the firstsemiconductor 61 with the interlayer insulating layers (the sixthinorganic insulating layer 22 d and the seventh inorganic insulatinglayer 22 e) interposed therebetween, and are electrically coupled to thefirst semiconductor 61 through the contact holes H1 and H2,respectively, provided in the interlayer insulating layers. Theplanarizing film covers the source electrode 62 and the drain electrode63. That is, the first inorganic insulating layer 25 is provided in alayer different from the interlayer insulating layers included in thefirst switching element Tr, and serves as the barrier layer that reducesthe permeation of hydrogen (H).

In the detection device 1 of the present embodiment, the first inorganicinsulating layer 25 is provided over the area overlapping the secondswitching element TrG. Thus, in the detection device 1, it is possibleto reduce changes in characteristics of the second switching elementsTrG that would be caused by the diffusion of hydrogen (H).

Second Embodiment

FIG. 8 is a sectional view illustrating a schematic sectionalconfiguration of a detection device according to a second embodiment. Inthe following description, the components described in theabove-described embodiment will be denoted by the same referencenumerals and will not be described.

As illustrated in FIG. 8, in a detection device 1A of the presentembodiment, a second inorganic insulating layer 25A is provided insteadof the first inorganic insulating layer 25. The second inorganicinsulating layer 25A is provided between the first organic insulatinglayer 23 a and the first switching element Tr in the normal direction ofthe insulating substrate 21. Specifically, the second inorganicinsulating layer 25A is provided on the upper side of the seventhinorganic insulating layer 22 e so as to cover the source electrode 62(signal line SGL) and the drain electrode 63 (third conductive layer67). The lower electrode 35 of the photodiode PD is provided on theupper side of the first organic insulating layer 23 a.

Also in the present embodiment, the second inorganic insulating layer25A can restrain the hydrogen (H) generated from the photodiode PD frompermeating the first switching element Tr.

The second inorganic insulating layer 25A is provided over the areaoverlapping the second switching element TrG and covers the sourceelectrode 82 and the drain electrode 83. This configuration can restrainthe hydrogen (H) generated from the photodiode PD from permeating thesecond switching element TrG.

Third Embodiment

FIG. 9 is a sectional view illustrating a schematic sectionalconfiguration of a detection device according to a third embodiment. Asillustrated in FIG. 9, in a detection device 1B of the presentembodiment, the second inorganic insulating layer 25A is provided inaddition to the first inorganic insulating layer 25. The first inorganicinsulating layer 25 is provided between the first organic insulatinglayer 23 a and the photodiode PD in the normal direction of theinsulating substrate 21. The second inorganic insulating layer 25A isprovided between the first organic insulating layer 23 a and the firstswitching element Tr. Specifically, the second inorganic insulatinglayer 25A covers the source electrode 62 (signal line SGL) and the drainelectrode 63 (third conductive layer 67) of the first switching elementTr. The first organic insulating layer 23 a is disposed so as to besandwiched between the first inorganic insulating layer 25 and thesecond inorganic insulating layer 25A in the normal direction of theinsulating substrate 21.

Also in the present embodiment, the first inorganic insulating layer 25and the second inorganic insulating layer 25A can restrain the hydrogen(H) generated from the photodiode PD from permeating the first switchingelement Tr. This configuration can increase the effect of blocking thehydrogen (H) generated from the photodiode PD to a higher level thanthat of the first and the second embodiments. The first inorganicinsulating layer 25 and the second inorganic insulating layer 25A arealso provided in the peripheral area GA and are provided over the areaoverlapping the second switching element TrG.

Fourth Embodiment

FIG. 10 is a plan view schematically illustrating the partial detectionarea of a detection device according to a fourth embodiment. FIG. 11 isa sectional view taken along line XI-XI′ of FIG. 10. As illustrated inFIG. 10, the first gate line GCLA (first gate electrode 64A) iselectrically coupled to the second gate line GCLB (second gate electrode64B) in an area surrounded by the second gate lines GCLB and the signallines SGL. The area surrounded by the second gate lines GCLB and thesignal lines SGL includes an area overlapping the second gate line GCLBbetween the adjacent signal lines SGL.

Specifically, the first gate line GCLA extends in the second directionDy, and the second gate line GCLB extends in the first direction Dx. Asecond gate line branch portion GCLBa branches from the second gate lineGCLB and extends in the second direction Dy. The first gate line GCLA isprovided so as to overlap the second gate line branch portion GCLBa. Agate line coupling layer CNGCL is provided so as to overlap portions ofthe first gate line GCLA and the second gate line GCLB.

As illustrated in FIG. 11, the second gate line GCLB is provided on theupper side of the fourth inorganic insulating layer 22 b. The first gateline GCLA is provided on the upper side of the sixth inorganicinsulating layer 22 d. The gate line coupling layer CNGCL is provided onthe upper side of the seventh inorganic insulating layer 22 e. The firstgate line GCLA is coupled to the gate line coupling layer CNGCL througha contact hole GH1 provided in the seventh inorganic insulating layer 22e. The second gate line GCLB is coupled to the gate line coupling layerCNGCL through a contact hole GH2 provided so as to penetrate from thefifth inorganic insulating layer 22 c to the seventh inorganicinsulating layer 22 e. This configuration electrically couples the firstgate line GCLA to the second gate line GCLB through the gate linecoupling layer CNGCL.

In the present embodiment, the first gate line GCLA (first gateelectrode 64A) is electrically coupled to the second gate line GCLB(second gate electrode 64B) in each of the partial detection areas PAA.Thus, the difference between a voltage applied to the first gateelectrode 64A and a voltage applied to the second gate electrode 64B canbe lowered as compared with the configuration in which the first gateline GCLA is electrically coupled to the second gate line GCLB in theperipheral area GA.

Fifth Embodiment

FIG. 12 is a sectional view illustrating a schematic sectionalconfiguration of a display device according to a fifth embodiment. Asillustrated in FIG. 12, a display device 120 includes the detectiondevice 1, a display panel 121, a touchscreen panel 122, and a coverglass 123. The display panel 121 may be, for example, an organicelectroluminescent (EL) (organic light-emitting diode (OLED)) displaypanel or an inorganic EL (micro-LED or mini-LED) display panel usinglight-emitting elements as the display elements. Alternatively, adisplay panel 121 may be a liquid crystal display (LCD) panel that usesliquid crystal elements as the display elements, or an electrophoreticdisplay (EPD) panel that uses electrophoretic elements as the displayelements. Although the amorphous silicon material is used as thephotoelectric conversion elements used in the detection device 1, anorganic material, for example, may instead be used.

The display panel 121 has a first principal surface 121 a and a secondprincipal surface 121 b that is a side opposite to the first principalsurface 121 a. The first principal surface 121 a is a surface that emitslight L1 from display elements toward the cover glass 123 to display animage. The first principal surface 121 a has a display area DA in whichthe image is displayed.

The touchscreen panel 122 uses, for example, a capacitance method todetect a finger Fg in contact with or in proximity to a surface of thecover glass 123. The touchscreen panel 122 is transmissive of light andcan transmit the light L1 and light L2 that has been reflected on aninterface between the cover glass 123 and air. The display device 120may have a configuration not including the touchscreen panel 122. Thedisplay panel 121 may be integrated with the touchscreen panel 122 ormay incorporate functions of the touchscreen panel 122.

The cover glass 123 is a member for protecting, for example, the displaypanel 121 and covers, for example, the display panel 121. The coverglass 123 is, for example, a glass substrate. The present disclosure isnot limited to using the cover glass 123. For example, a resin substratemay be provided above the touchscreen panel 122.

The detection device 1 is provided so as to face the second principalsurface 121 b of the display panel 121. The detection device 1 candetect the asperities of the surface of the finger Fg by detecting thelight L2 reflected on the interface between the cover glass 123 and air.Since the detection device 1 can be easily increased in area, thedetection area AA of the detection device 1 is provided so as to facethe entire display area DA of the display panel 121. The detection areaAA is not limited to this configuration. The detection area AA may facea portion of the display area DA of the display panel 121.

While the preferred embodiments of the present disclosure have beendescribed above, the present disclosure is not limited to theembodiments described above. The content disclosed in the embodiments ismerely an example, and can be variously modified within the scope notdeparting from the gist of the present disclosure. Modificationsappropriately made within the scope not departing from the gist of thepresent disclosure naturally belong to the technical scope of thepresent disclosure.

For example, each of the detection devices 1, 1A, and 1B is not limitedto the case of being used as the fingerprint sensor for detecting thefingerprint of the finger Fg. Each of the detection devices 1, 1A, and1B can be used as a biosensor that detects various types of biologicalinformation such as a blood vessel image of the finger Fg or the palm, apulse wave, pulsation, and a blood oxygen concentration.

What is claimed is:
 1. A detection device comprising: an insulatingsubstrate; a plurality of photoelectric conversion elements that arearranged in a detection area of the insulating substrate, and each ofwhich is configured to receive light and output a signal correspondingto the received light; a first switching element that is provided foreach photoelectric conversion element and comprises a firstsemiconductor, a source electrode, and a drain electrode; and aninorganic insulating layer provided between the photoelectric conversionelement and the first switching element in a normal direction of theinsulating substrate.
 2. The detection device according to claim 1,further comprising a planarizing film that covers the first switchingelement, wherein the inorganic insulating layer is provided between theplanarizing film and the photoelectric conversion element in the normaldirection of the insulating substrate.
 3. The detection device accordingto claim 1, further comprising a planarizing film that covers the firstswitching element, wherein the inorganic insulating layer is providedbetween the planarizing film and the first switching element in thenormal direction of the insulating substrate.
 4. The detection deviceaccording to claim 3, wherein the source electrode and the drainelectrode are provided above the first semiconductor with an interlayerinsulating layer interposed between the source and drain electrodes andthe first semiconductor, and each of the source electrode and the drainelectrode is electrically coupled to the first semiconductor through acontact hole provided in the interlayer insulating layer, and theinorganic insulating layer covers the source electrode and the drainelectrode.
 5. The detection device according to claim 1, furthercomprising: a plurality of gate lines coupled to the first switchingelements and extending in a first direction; and a gate line drivecircuit that comprises a second switching element comprising a secondsemiconductor, is provided in a peripheral area outside the detectionarea, and is configured to drive the gate lines, wherein the inorganicinsulating layer is provided over an area overlapping the secondswitching element.
 6. The detection device according to claim 5, whereinthe first semiconductor is an oxide semiconductor, and the secondsemiconductor is of polysilicon.
 7. The detection device according toclaim 1, wherein the inorganic insulating layer comprises a firstinorganic insulating layer and a second inorganic insulating layer, thedetection device further comprises a planarizing film that covers thefirst switching element, and the first inorganic insulating layer isprovided between the planarizing film and the photoelectric conversionelement, and the second inorganic insulating layer is provided betweenthe planarizing film and the first switching element, in the normaldirection of the insulating substrate.
 8. The detection device accordingto claim 7, wherein the source electrode and the drain electrode areprovided above the first semiconductor with an interlayer insulatinglayer interposed between the source and drain electrodes and the firstsemiconductor, and each of the source electrode and the drain electrodeis electrically coupled to the first semiconductor through a contacthole provided in the interlayer insulating layer, and the secondinorganic insulating layer covers the source electrode and the drainelectrode.
 9. The detection device according to claim 1, wherein thefirst switching element comprises a first gate electrode and a secondgate electrode provided with the first semiconductor interposedtherebetween in the normal direction of the insulating substrate, thedetection device further comprises: a plurality of gate lines coupled tothe first switching elements and extending in a first direction; and aplurality of signal lines coupled to the first switching elements andintersecting the first direction, and the first gate electrode iselectrically coupled to the second gate electrode in an area surroundedby the gate lines and the signal lines.
 10. A display device comprising:the detection device according to claim 1; and a display panel thatcomprises display elements to display an image and is disposed so as toface the detection device.